1. Field of the Invention
This invention resides in the field of preparative chromatograph columns, and in particular, the components associated with such columns for filling the columns with packed beds of separation media, removing such media from the columns, and cleaning the columns between uses.
2. Description of the Prior Art
Preparative chromatography is the use of chromatographic separation principles to isolate individual chemical species from mixtures at quantities sufficient for use of the isolated species on a commercial scale, rather than for analytical purposes. One of the various types of equipment in which preparative chromatography is performed is a large-diameter vertical column containing a packed bed of solid or semi-solid separation medium serving as a stationary phase. The mixture from which the species of interest is to be isolated is passed through the column by way of a mobile phase that flows through the packed bed in a generally plug-flow regime. The width of the column is sufficient, exceeding 1 meter in some cases, to accommodate a commercially useful throughput rate, while the depth of the column is limited to maintain a pressure drop that is low enough to avoid the need for a high pump pressure or high pumping power. Columns of this type contain a plunger or piston head that is lowered to contact and compress the solid phase to the desired height. The mobile phase enters the column through the plunger which includes a distributor plate to spread the mobile phase across the full width of the bed. At the floor of the column is a plate that includes a filter, a distribution system, and a fluid port. The pore size of the filter is smaller than the particle size of the packed bed, thus retaining the packed bed in the column, yet large enough to allow the mobile phase to pass. The distribution system at the column floor ensures that the mobile phase leaving the column is drawn from the full width of the column, the top and bottom distribution systems together ensuring that maximal use is made of the bed.
The use of a preparative chromatography column of this type requires that the packed bed be periodically removed and replaced and that the column itself and its various supply and discharge lines be cleaned. With large diameter columns, these operations typically require opening of the column and other operations that are costly both in labor and capital. These concerns are particularly acute when operation of the column requires a clean room or a high clearance above the column, or both.